Soft Decoding of Rate-Compatible Polar Codes

ABSTRACT

A node (110, 115) receives (804) transmissions associated with a given set of information bits, wherein each of the transmissions use a different polar code and share one or more information bits of the given set of information bits. The node determines (808), at each of a plurality of polar decoders (505, 605) of the node, soft information for each information bit included in an associated one of the transmissions, wherein each of the plurality of polar decoders is associated with a different transmission of the transmissions. The node provides (812), from each polar decoder of the plurality to one or more other polar decoders of the plurality, the determined soft information for any information bits shared by their respective associated transmissions, and uses (816) the provided soft information in an iterative decoding process to decode one or more of the received transmissions.

TECHNICAL FIELD The present disclosure relates, in general, to wirelesscommunications and, more particularly, to soft decoding ofrate-compatible polar codes. BACKGROUND

Polar codes, proposed by E. Arikan in “Channel Polarization: A Methodfor Constructing Capacity-Achieving Codes for Symmetric Binary-InputMemoryless Channels,” IEEE Transactions on Information Theory, vol. 55,pp. 3051-3073, July 2009 (hereinafter “Arikan”), are the first class ofconstructive coding schemes that are provable to achieve the symmetriccapacity of the binary-input discrete memoryless channels under alow-complexity successive cancellation (SC) decoder. However, thefinite-length performance of polar codes under SC is not competitivecompared to other modern channel coding schemes such as low-densityparity-check (LDPC) codes and Turbo codes. Later, a SC list (SCL)decoder was proposed by I. Tal and A. Vardy in “List Decoding of polarcodes,” Proceedings of IEEE Symp. Inf. Theory, pp. 1-5, 2011(hereinafter “Tal”), which can approach the performance of the optimalmaximum-likelihood (ML) decoder. By concatenating simple CyclicRedundancy Check (CRC) coding, it was shown that the performance ofconcatenated polar codes is competitive with that of well-optimized LDPCand Turbo codes. As a result, polar codes are being considered as acandidate for future wireless communication systems, such as 5G.

The main idea of polar coding is to transform a pair of identicalbinary-input channels into two distinct channels of different qualities,one better and one worse than the original binary-input channel. Byrepeating such a pair-wise polarizing operation on a set of 2^(M)independent uses of a binary-input channel, a set of 2^(M)“bit-channels” of varying qualities can be obtained. Some of these bitchannels are nearly perfect (i.e., error free) while the rest of themare nearly useless (i.e., totally noisy). The point is to use the nearlyperfect channel to transmit data to the receiver while setting the inputto the useless channels to have fixed or frozen values (e.g., 0) knownto the receiver. For this reason, those input bits to the nearly uselessand the nearly perfect channel are commonly referred to as frozen bitsand non-frozen (or information) bits, respectively. Only the non-frozenbits are used to carry data in a polar code.

Wireless broadband systems require flexible and adaptive transmissiontechniques because they operate in the presence of time-varyingchannels. For such systems, hybrid automatic repeat request based onincremental redundancy (HARQ-IR) schemes are often used, where paritybits are sent in an incremental fashion depending on the quality of thetime-varying channel. IR systems require the use of rate-compatiblepunctured codes. According to the rate requirement, an appropriatenumber of coded bits are sent by the transmitter during the firsttransmission or subsequent retransmissions. Here, the set of coded bitsof a higher rate code should be a subset of the set of coded bits of alower rate code. In HARQ-IR systems, therefore, if the receiver fails todecode at a particular rate, it only needs to request additional codedbits to be transmitted in subsequent retransmissions by the transmitter.There has been extensive research on the construction of rate-compatibleTurbo codes and LDPC codes. However, there is relatively few researchdone on rate-compatible polar codes.

FIG. 1 illustrates an example of polar code structure in a firsttransmission in HARQ incremental redundancy. More particularly, FIG. 1illustrates the structure of a length-8 polar code. In the firsttransmission illustrated in FIG. 1, six out of eight bit channels of thelength-8 polar code are loaded with data (non-frozen or information bitsu₀ through u₅) while the rest are frozen (assigned a value of zero,which is known to the receiver), giving an overall code rate of ¾.

In both S. Hong, D. Hui, I. Maric, “Capacity Achieving Rate-CompatiblePolar Codes,” Proc. ISIT, Bacelona, July 2016 (hereinafter “Hong”) andB. Li, D. Tse, K. Chen, H. Shen, “Capacity-Achieving Rateless PolarCodes, ” Proc. ISIT, Bacelona, July 2016, a new class of rate-compatiblepolar codes was introduced to allow HARQ-IR retransmissions. For HARQschemes that adopt this class of codes, each transmission (orretransmission) uses a separate polar code (with its own associatedpolar encoder) to generate a separate code block. A portion ofnon-frozen bits (e.g., a portion of non-frozen bits u₀ through u₅ in theexample of FIG. 1) used in each of the previous transmissions areaggregated, re-encoded and transmitted in a subsequent retransmission.The amount of non-frozen bits taken from each previous transmission toform the new retransmission is determined in such a way that each of theprevious (re-)transmissions would result in the same effective (lowered)coding rate if all subsequent transmissions are decoded successfully,and the decoded bits are used as frozen bits.

The aforementioned class of rate-compatible polar codes can beillustrated by an example using the three transmissions illustrated inFIGS. 1-3. As noted above, in the first transmission illustrated in FIG.1, six out of the eight bit channels of a length-8 polar code are loadedwith data while the rest are frozen, giving an overall code rate of ¾.If the receiver fails to decode the six information bits (u₀ throughu₅), another length-8 polar code may be used to re-transmit the leastreliable bits, which in the example of FIG. 1 are u₃, u₄, and u₅. Thisfirst retransmission illustrated in FIG. 2, described below.

FIG. 2 illustrates an example of polar code structure in a secondtransmission (i.e., first retransmission) in HARQ incrementalredundancy. If the receiver fails to decode the six information bits inthe first transmission, another length-8 polar code such as the oneillustrated in FIG. 2 may be used to re-transmit the three leastreliable bits (u₃, u₄, u₅). In the example of FIG. 2, the code rate inthe 2^(nd) code block is ⅜. Thus, the effective code rate of the 1^(st)code block in the first transmission of FIG. 1 is also reduced from ¾ to⅜ if the bits (u₃, u₄, u₅) are successively decoded by the receiver fromthe 2^(nd) code block and used as frozen bits to decode the first codeblock. If the receiver fails again to decode the 2^(nd) transmission(i.e., first retransmission) of FIG. 2, the least reliable bit of the2^(nd) transmission, which in the example of FIG. 2 is u₃, and the nextleast reliable bit u₂ of the 1^(st) transmission in the example of FIG.1 (assuming not all data bits in the 2^(nd) transmission have beensuccessively decoded) are retransmitted using another length-8 polarcode.

FIG. 3 illustrates an example of polar code structure in a thirdtransmission (i.e., second retransmission) in HARQ incrementalredundancy. If the receiver fails again to decode the secondtransmission (i.e., first retransmission) of FIG. 2, the least reliablebit of the 2^(nd) transmission, which in the example of FIG. 2 is u₃,and the next least reliable bit u₂ of the 1^(st) transmission in theexample of FIG. 1 (assuming not all data bits in the 2^(nd) transmissionhas been successively decoded) are retransmitted using another length-8polar code such as the one illustrated in the example of FIG. 3. In thiscase, the effective code rates of all three code blocks of the threetransmissions are all reduced to from ⅜ to ¼, assuming that all databits in subsequent retransmissions are successively decoded and used asfrozen bits in corresponding previous transmissions.

A method of successively decoding over multiple transmissions was alsoproposed in Hong. In this method, a decoder first decodes the mostrecent code block in the last retransmission and then uses the decoded(hard) bits as frozen bits to decode the previous (re)transmission untilthe first transmission is decoded. It can be shown that this simpledecoding method achieves the aggregated capacity of all retransmissions.

Although the aforementioned successive decoding method over multipletransmissions achieves capacity, the decoding method is suboptimal interms of block error performance. The reasons for this are twofold.First, decoding of code blocks of subsequent retransmissions does nottake into account the information contained in the previoustransmissions. As a result, the block error performance is limited bythe block length of each individual transmission and does not benefitfrom the sum block length over all transmissions. Second, exchange ofhard bits between one code block and another does not account for thereliability of the decoded information (non-frozen) bits.

SUMMARY

To address the foregoing problems with existing approaches, disclosed isa method in a node. The method comprises receiving a plurality oftransmissions associated with a given set of information bits, whereineach of the plurality of transmissions use a different polar code andshare one or more information bits of the given set of information bits.The method comprises determining, at each of a plurality of polardecoders of the node, soft information for each information bit includedin an associated one of the plurality of transmissions, wherein each ofthe plurality of polar decoders is associated with a differenttransmission of the plurality of transmissions. The method comprisesproviding, from each polar decoder of the plurality to one or more otherpolar decoders of the plurality, the determined soft information for anyinformation bits shared by their respective associated transmissions,and using the provided soft information in an iterative decoding processto decode one or more of the received plurality of transmissions.

In certain embodiments, the soft information may comprise one or more ofprobabilities or log-likelihood ratios. In certain embodiments, themethod may comprise scaling the soft information by a factor.

In certain embodiments, the soft information may be determined based ona log-likelihood ratio of one or more channel bits received from ademodulator and the soft information provided from the one or more otherpolar decoders of the plurality for any information bits shared by theirrespective associated transmissions. The soft information provided fromthe one or more other polar decoders of the plurality may comprise softinformation from one or more polar decoders of previous transmissionsfor a subset of information bits shared by their respectivetransmissions. The soft information provided from the one or more otherpolar decoders of the plurality may comprise soft information from oneor more polar decoders of subsequent transmissions for a subset ofinformation bits shared by their respective transmissions.

In certain embodiments, the method may comprise determining, at a firstpolar decoder associated with a first transmission of the plurality oftransmissions, soft information for each information bit in the firsttransmission. The method may comprise providing, from the first polardecoder associated with the first transmission to a second polar decoderassociated with a second transmission, the soft information for eachinformation bit in the first transmission included in a subset ofinformation bits shared by the first transmission and the secondtransmission. The method may comprise determining, at the second polardecoder associated with the second transmission of the plurality oftransmissions, soft information for each information bit in the subsetof information bits shared by the first transmission and the secondtransmission. The method may comprise providing, from the second polardecoder associated with the second transmission to the first polardecoder associated with the first transmission, the soft information foreach information bit in the subset of information bits shared by thefirst transmission and the second transmission. In certain embodiments,the method may comprise determining, by the first polar decoder, a harddecision for each information bit of the first transmission based on thesoft information provided by the second polar decoder for eachinformation bit in the subset of information bits shared by the firsttransmission and the second transmission.

In certain embodiments, the method may comprise storing the determinedsoft information. The method may comprise retrieving the stored softinformation and using it to decode a first transmission of the pluralityof transmissions and another transmission of the plurality oftransmissions.

In certain embodiments, the plurality of transmissions associated with agiven set of information bits may comprise an initial transmission and aplurality of retransmissions. The plurality of polar decoders maycomprise successive cancellation decoders.

Also disclosed is a node. The node comprises processing circuitry. Theprocessing circuitry is configured to receive a plurality oftransmissions associated with a given set of information bits, whereineach of the plurality of transmissions use a different polar code andshare one or more information bits of the given set of information bits.The processing circuitry is configured to determine, at each of aplurality of polar decoders of the node, soft information for eachinformation bit included in an associated one of the plurality oftransmissions, wherein each of the plurality of polar decoders isassociated with a different transmission of the plurality oftransmissions. The processing circuitry is configured to provide, fromeach polar decoder of the plurality to one or more other polar decodersof the plurality, the determined soft information for any informationbits shared by their respective associated transmissions, and use theprovided soft information in an iterative decoding process to decode oneor more of the received plurality of transmissions.

Certain embodiments of the present disclosure may provide one or moretechnical advantages. For example, certain embodiments mayadvantageously enable a decoder of a class of rate-compatible polarcodes to effectively take advantage of the aggregated block lengthsafter multiple transmissions to improve the block error rate and thenumber of retransmissions needed to pass CRC for a target block errorrate. Other advantages may be readily apparent to one having skill inthe art. Certain embodiments may have none, some, or all of the recitedadvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosed embodiments and theirfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates an example of polar code structure in a firsttransmission in HARQ incremental redundancy;

FIG. 2 illustrates an example of polar code structure in a secondtransmission (i.e., first retransmission) in HARQ incrementalredundancy;

FIG. 3 illustrates an example of polar code structure in a thirdtransmission (i.e., second retransmission) in HARQ incrementalredundancy;

FIG. 4 is a block diagram illustrating an embodiment of a network, inaccordance with certain embodiments;

FIG. 5 illustrates an example of iterative decoding using two differenttransmissions in HARQ incremental redundancy, in accordance with certainembodiments;

FIG. 6 illustrates an example of iterative decoding using N differenttransmissions in HARQ incremental redundancy, in accordance with certainembodiments;

FIG. 7 illustrates an example of how soft and hard information isgenerated in successive decoding of polar codes, in accordance withcertain embodiments;

FIG. 8 is a flow diagram of a method in a node, in accordance withcertain embodiments;

FIG. 9 is a block schematic of an exemplary UE, in accordance withcertain embodiments;

FIG. 10 is a block schematic of an exemplary eNodeB, in accordance withcertain embodiments;

FIG. 11 is a block schematic of an exemplary wireless device, inaccordance with certain embodiments;

FIG. 12 is a block schematic of an exemplary network node, in accordancewith certain embodiments;

FIG. 13 is a block schematic of an exemplary radio network controller orcore network node, in accordance with certain embodiments;

FIG. 14 is a block schematic of an exemplary wireless device, inaccordance with certain embodiments; and

FIG. 15 is a block schematic of an exemplary network node, in accordancewith certain embodiments.

DETAILED DESCRIPTION

As described above, existing approaches to successively decoding polarcodes over multiple transmissions use a decoder that first decodes themost recent code block in the last retransmission and then uses thedecoded (hard) bits as frozen bits to decode the previous(re)transmission until the first transmission is decoded. Although itachieves capacity, there are certain deficiencies associated with suchan approach. For example, this approach to decoding is suboptimal interms of block error performance. The reasons for this are twofold.First, decoding of code blocks of subsequent retransmissions does nottake into account the information contained in the previoustransmissions. As a result, the block error performance is limited bythe block length of each individual transmission and does not benefitfrom the sum block length over all transmissions. Second, exchange ofhard bits between one code block and another does not account for thereliability of the decoded information (non-frozen) bits.

The present disclosure contemplates various embodiments that may addressthese and other deficiencies associated with existing approaches. Forexample, embodiments described herein relate to a decoding process thatallows soft information to be exchanged among code blocks of differenttransmissions associated with a given set of information bits, so thatthe soft information of an individual information bit is exchanged amongall code blocks that contain the information bit. This allows eachinformation bit to derive benefit from every (re)transmission thatcontains the bit, instead of only the most recent (re)transmission. Incertain embodiments, the soft information may be expressed in the formof probabilities or log-likelihood ratios (LLR).

According to one example embodiment, a method in a node (e.g., wirelessdevice or network node) is disclosed. The node receives a plurality oftransmissions associated with a given set of information bits, whereineach of the plurality of transmissions use a different polar code andshare one or more information bits of the given set of information bits.The node determines, at each of a plurality of polar decoders of thenode, soft information for each information bit included in anassociated one of the plurality of transmissions, wherein each of theplurality of polar decoders is associated with a different transmissionof the plurality of transmissions. The node provides, from each polardecoder of the plurality to one or more other polar decoders of theplurality, the determined soft information for any information bitsshared by their respective associated transmissions, and uses theprovided soft information in an iterative decoding process to decode oneor more of the received plurality of transmissions.

Certain embodiments of the present disclosure may provide one or moretechnical advantages. For example, certain embodiments mayadvantageously enable a decoder of a class of rate-compatible polarcodes to effectively take advantage of the aggregated block lengthsafter multiple transmissions to improve the block error rate and thenumber of retransmissions needed to pass CRC for a target block errorrate. Other advantages may be readily apparent to one having skill inthe art. Certain embodiments may have none, some, or all of the recitedadvantages.

In the following description, numerous specific details are set forth.However, it is understood that embodiments of the present disclosure maybe practiced without these specific details. In other instances,well-known circuits, structures and techniques have not been shown indetail in order not to obscure the understanding of this description.Those of ordinary skill in the art, with the included descriptions, willbe able to implement appropriate functionality without undueexperimentation.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” “certain embodiments,” etc., indicate that theembodiment(s) described may include a particular feature, structure, orcharacteristic, but every embodiment may not necessarily include theparticular feature, structure, or characteristic. Moreover, such phrasesare not necessarily referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with an embodiment, it is submitted that it is within theknowledge of one skilled in the art to implement such feature,structure, or characteristic in connection with other embodimentswhether or not explicitly described.

In the following description and claims, the terms “coupled” and“connected,” along with their derivatives, may be used. It should beunderstood that these terms are not intended as synonyms for each other.“Coupled” is used to indicate that two or more elements, which may ormay not be in direct physical or electrical contact with each other,co-operate or interact with each other. “Connected” is used to indicatethe establishment of communication between two or more elements that arecoupled with each other.

FIG. 4 is a block diagram illustrating an embodiment of a network 100,in accordance with certain embodiments. Network 100 includes one or morewireless devices 110 and one or more network nodes 115. Wireless devices110 may communicate with network nodes 115 over a wireless interface.For example, wireless device 110 may transmit wireless signals to one ormore of network nodes 115, and/or receive wireless signals from one ormore of network nodes 115. The wireless signals may contain voicetraffic, data traffic, control signals, and/or any other suitableinformation. In some embodiments, an area of wireless signal coverageassociated with a network node 115 may be referred to as a cell 125. Insome embodiments, wireless device 110 may have device-to-device (D2D)capability. Thus, wireless devices 110 may be able to receive signalsfrom and/or transmit signals directly to another wireless device.

In certain embodiments, network nodes 115 may interface with a radionetwork controller. The radio network controller may control networknodes 115 and may provide certain radio resource management functions,mobility management functions, and/or other suitable functions. Incertain embodiments, the functions of the radio network controller maybe included in network node 115. The radio network controller mayinterface with a core network node. In certain embodiments, the radionetwork controller may interface with the core network node via aninterconnecting network 120. Interconnecting network 120 may refer toany interconnecting system capable of transmitting audio, video,signals, data, messages, or any combination of the preceding.Interconnecting network 120 may include all or a portion of one or moreInternet Protocol (IP) networks, public switched telephone networks(PSTNs), packet data networks, optical networks, public or private datanetworks, local area networks (LANs), wireless local area networks(WLANs), wired networks, wireless networks, metropolitan area networks(MANs), wide area networks (WAN), a local, regional, or globalcommunication or computer network such as the Internet, an enterpriseintranet, or any other suitable communication links, includingcombinations thereof, to enable communication between devices.

In some embodiments, the core network node may manage the establishmentof communication sessions and various other functionalities for wirelessdevices 110. Wireless devices 110 may exchange certain signals with thecore network node using the non-access stratum layer. In non-accessstratum signaling, signals between wireless devices 110 and the corenetwork node may be transparently passed through the radio accessnetwork (RAN). In certain embodiments, network nodes 115 may interfacewith one or more network nodes over an internode interface, such as, forexample, an X2 interface.

As described above, example embodiments of network 100 may include oneor more wireless devices 110, and one or more different types of networknodes 115 capable of communicating (directly or indirectly) withwireless devices 110.

In some embodiments, the non-limiting term wireless device is used.Wireless devices 110 described herein can be any type of wireless devicecapable, configured, arranged and/or operable to communicate wirelesslywith network nodes 115 and/or another wireless device, for example overradio signals. Communicating wirelessly may involve transmitting and/orreceiving wireless signals using electromagnetic signals, radio waves,infrared signals, and/or other types of signals suitable for conveyinginformation through air. In particular embodiments, wireless devices maybe configured to transmit and/or receive information without directhuman interaction. For instance, a wireless device may be designed totransmit information to a network on a predetermined schedule, whentriggered by an internal or external event, or in response to requestsfrom the network. Generally, a wireless device may represent any devicecapable of, configured for, arranged for, and/or operable for wirelesscommunication, for example radio communication devices. Examples ofwireless devices include, but are not limited to, user equipment (UEs)such as smart phones. Further examples include wireless cameras,wireless-enabled tablet computers, laptop-embedded equipment (LEE),laptop-mounted equipment (LME), USB dongles, and/or wirelesscustomer-premises equipment (CPE). Wireless device 110 may also be aradio communication device, target device, D2D UE,machine-type-communication (MTC) UE or UE capable of machine-to-machine(M2M) communication, low-cost and/or low-complexity UE, a sensorequipped with UE, Tablet, mobile terminals, an Internet of Things (IoT)device, or a Narrowband IoT (NB-IOT) device, or any other suitabledevices.

As one specific example, wireless device 110 may represent a UEconfigured for communication in accordance with one or morecommunication standards promulgated by the 3^(rd) Generation PartnershipProject (3GPP), such as 3GPP's Global System for New Radio (NR), MobileCommunications (GSM), Universal Mobile Telecommunications System (UMTS),Long Term Evolution (LTE), and/or other suitable 2G, 3G, 4G or 5Gstandards or other suitable standards. As used herein, a “UE” may notnecessarily have a “user” in the sense of a human user who owns and/oroperates the relevant device. Instead, a UE may represent a device thatis intended for sale to, or operation by, a human user but that may notinitially be associated with a specific human user.

Wireless device 110 may support D2D communication, for example byimplementing a 3GPP standard for sidelink communication, and may in thiscase be referred to as a D2D communication device.

As yet another specific example, in an IoT scenario, a wireless devicemay represent a machine or other device that performs monitoring and/ormeasurements, and transmits the results of such monitoring and/ormeasurements to another wireless device and/or a network node. Thewireless device may in this case be a M2M device, which may in a 3GPPcontext be referred to as a MTC device. As one particular example, thewireless device may be a UE implementing the 3GPP NB-IoT standard.Particular examples of such machines or devices are sensors, meteringdevices such as power meters, industrial machinery, or home or personalappliances (e.g., refrigerators, televisions, personal wearables such aswatches, etc.). In other scenarios, a wireless device may represent avehicle or other equipment that is capable of monitoring and/orreporting on its operational status or other functions associated withits operation.

Wireless device 110 as described above may represent the endpoint of awireless connection, in which case the device may be referred to as awireless terminal. Furthermore, a wireless device as described above maybe mobile, in which case it may also be referred to as a mobile deviceor a mobile terminal.

As depicted in FIG. 1, wireless device 110 may be any type of wirelessendpoint, mobile station, mobile phone, wireless local loop phone,smartphone, user equipment, desktop computer, Personal Digital Assistant(PDA), cell phone, tablet, laptop, Voice Over IP (VoIP) phone orhandset, which is able to wirelessly send and receive data and/orsignals to and from a network node, such as network node 115 and/orother wireless devices.

Wireless device 110 (e.g., an end station, a network device) may storeand transmit (internally and/or with other electronic devices over anetwork) code (composed of software instructions) and data usingmachine-readable media, such as non-transitory machine-readable media(e.g., machine-readable storage media such as magnetic disks; opticaldisks; read-only memory (ROM); flash memory devices; phase changememory) and transitory machine-readable transmission media (e.g.,electrical, optical, acoustical or other form of propagated signals—suchas carrier waves, infrared signals). In addition, wireless devices 110may include hardware such as a set of one or more processors coupled toone or more other components, such as one or more non-transitorymachine-readable media (to store code and/or data), user input/outputdevices (e.g., a keyboard, a touchscreen, and/or a display), and networkconnections (to transmit code and/or data using propagating signals).The coupling of the set of processors and other components is typicallythrough one or more busses and bridges (also termed as bus controllers).Thus, a non-transitory machine-readable medium of a given electronicdevice typically stores instructions for execution on one or moreprocessors of that electronic device. One or more parts of an embodimentdescribed herein may be implemented using different combinations ofsoftware, firmware, and/or hardware.

Also, in some embodiments generic terminology, “network node” is used.As used herein, “network node” refers to equipment capable, configured,arranged and/or operable to communicate directly or indirectly with awireless device and/or with other equipment (e.g., another network node)in the wireless communication network that enable and/or providewireless access to the wireless device. Examples of network nodesinclude, but are not limited to, access points (APs), in particularradio access points. A network node may represent base stations (BSs),such as radio base stations. Particular examples of radio base stationsinclude Node Bs, evolved Node Bs (eNBs), Master eNB (MeNB), SecondaryeNB (SeNB), and gNBs. Base stations may be categorized based on theamount of coverage they provide (or, stated differently, their transmitpower level) and may then also be referred to as femto base stations,pico base stations, micro base stations, or macro base stations.“Network node” also includes one or more (or all) parts of a distributedradio base station such as centralized digital units and/or remote radiounits (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Suchremote radio units may or may not be integrated with an antenna as anantenna integrated radio. Parts of a distributed radio base stations mayalso be referred to as nodes in a distributed antenna system (DAS).

As a particular non-limiting example, a base station may be a relay nodeor a relay donor node controlling a relay.

Yet further examples of network nodes include a network node belongingto a Master Cell Group (MCG), a network node belonging to a SecondaryCell Group (SCG), multi-standard radio (MSR) radio equipment such as MSRBSs, network controllers such as radio network controllers (RNCs) orbase station controllers (BSCs), base transceiver stations (BTSs),transmission points, transmission nodes, Multi-cell/multicastCoordination Entities (MCEs), core network nodes (e.g., Mobile SwitchingCenters (MSCs), Mobility Management Entities (MMEs), etc.), Operationand Maintenance (O&M) nodes, Operations Support System (OSS) nodes,Self-Organizing Network (SON) nodes, positioning nodes (e.g., EvolvedServing Mobile Location Center (E-SMLCs)), minimization of drive tests(MDTs), or any other suitable network node. More generally, however,network nodes may represent any suitable device (or group of devices)capable, configured, arranged, and/or operable to enable and/or providea wireless device access to the wireless communication network or toprovide some service to a wireless device that has accessed the wirelesscommunication network.

Network nodes 115 may be a piece of networking equipment, includinghardware and software, which communicatively interconnects otherequipment on the network (e.g., wireless devices 110, other networkdevices, end stations). Some network devices are “multiple servicesnetwork devices” that provide support for multiple networking functions(e.g., routing, bridging, switching, Layer 2 aggregation, session bordercontrol, Quality of Service, and/or subscriber management), and/orprovide support for multiple application services (e.g., data, voice,and video). Subscriber end stations (e.g., servers, workstations,laptops, netbooks, palm tops, mobile phones, smartphones, multimediaphones, VOIP phones, user equipment, terminals, portable media players,GPS units, gaming systems, set-top boxes) access content/servicesprovided over the Internet and/or content/services provided on virtualprivate networks (VPNs) overlaid on (e.g., tunneled through) theInternet. The content and/or services are typically provided by one ormore end stations (e.g., server end stations) belonging to a service orcontent provider or end stations participating in a peer to peerservice, and may include, for example, public webpages (e.g., freecontent, store fronts, search services), private webpages (e.g.,username/password accessed webpages providing email services), and/orcorporate networks over VPNs. Typically, subscriber end stations arecoupled (e.g., through CPE coupled to an access network (wired orwirelessly)) to edge network devices, which are coupled (e.g., throughone or more core network devices) to other edge network devices, whichare coupled to other end stations (e.g., server end stations). One ofordinary skill in the art would realize that any network device, endstation or other network apparatus can perform various functionsdescribed herein.

The term “node” may be used herein generically to refer both to wirelessdevices and network nodes, as each is respectively described above.

The terminology such as network node and wireless device should beconsidered non-limiting and does in particular not imply a certainhierarchical relation between the two; in general “network node” couldbe considered as a first device and “wireless device” as a seconddevice, and these two devices communicate with each other over someradio channel.

Example embodiments of wireless devices 110, network nodes 115, andother network nodes (such as radio network controller or core networknode) are described in more detail below with respect to FIGS. 9-15.

Although FIG. 1 illustrates a particular arrangement of network 100, thepresent disclosure contemplates that the various embodiments describedherein may be applied to a variety of networks having any suitableconfiguration. For example, network 100 may include any suitable numberof wireless devices 110 and network nodes 115, as well as any additionalelements suitable to support communication between wireless devices orbetween a wireless device and another communication device (such as alandline telephone). In different embodiments, the wireless network 100may comprise any number of wired or wireless networks, network nodes,base stations, controllers, wireless devices, relay stations, and/or anyother components that may facilitate or participate in the communicationof data and/or signals whether via wired or wireless connections.

Furthermore, the embodiments described herein may be implemented in anyappropriate type of telecommunication system using any suitablecomponents, and are applicable to any radio access technology (RAT) ormulti-RAT systems in which a wireless device receives and/or transmitssignals (e.g., data). For example, the various embodiments describedherein may be applicable to NR, LTE, LTE-Advanced, 5G, UMTS, HSPA, GSM,cdma2000, WCDMA, WiMax, UMB, WiFi, another suitable RAT, or any suitablecombination of one or more RATs. Thus, network 100 may represent anytype of communication, telecommunication, data, cellular, and/or radionetwork or other type of system. In particular embodiments, the network100 may be configured to operate according to specific standards orother types of predefined rules or procedures. Thus, particularembodiments of the wireless communication network may implementcommunication standards, such as NR, GSM, UMTS, LTE, and/or othersuitable 2G, 3G, 4G, or 5G standards; wireless local area network (WLAN)standards, such as the IEEE 802.11 standards; and/or any otherappropriate wireless communication standard, such as the WorldwideInteroperability for Microwave Access (WiMax), Bluetooth, and/or ZigBeestandards.

Although certain embodiments may be described in the context of wirelesstransmissions in the downlink (DL), the present disclosure contemplatesthat the various embodiments are equally applicable in the uplink (UL).

As described above, the present disclosure contemplates variousembodiments directed to a decoding process (e.g., in a node of network100, such as wireless device 110 or network node 115) that allows softinformation (typically in the format of extrinsic LLR) to be exchangedamong code blocks of different transmissions associated with a given setof information bits, so that the soft information of an individualinformation bit is exchanged among all code blocks that contain theinformation bit. This allows each information bit to derive benefit fromevery (re)transmission that contains the bit, instead of only the mostrecent (re)transmission. In certain embodiments, the soft informationmay be expressed in the form of probabilities or log-likelihood ratios(LLR). The soft information may be derived in multiple ways. In oneexample embodiment, the soft information is derived based on the maximuma posteriori (MAP) probability of each bit. In another exampleembodiment, the soft information is derived based on the maximumlikelihood (ML) probability of the codeword. Although certainembodiments may be described using examples in which the softinformation is in the format of extrinsic LLR, the present disclosure isnot limited to such an example. Rather, the present disclosurecontemplates that other types of soft information may be used. As anadditional non-limiting example, in certain embodiments the softinformation may be in the format of a Euclidean distance calculation.

FIG. 5 illustrates an example of iterative decoding using two differenttransmissions in HARQ incremental redundancy, in accordance with certainembodiments. In the example embodiment of FIG. 5, an iterative decodingprocess is described using, as an example, the first and secondtransmissions described above in relation to FIGS. 1 and 2. Eachtransmission is associated with a polar decoder 505 of a node. In theexample of FIG. 5, the first transmission is associated with a firstpolar decoder 505 a, and the second transmission is associated with asecond polar decoder 505 b. A generalization of this example embodimentto any number of transmissions is further described below in relation toFIG. 6. One important observation is that the first and secondtransmissions described above in FIGS. 1 and 2, respectively,essentially use two different polar codes, and share a subset ofinformation bits. As a result, these two different codes can be puttogether in an iterative decoding process, as shown in the example ofFIG. 5.

Let extrinsic-LLR(u_(i), n^(th) tx) denote the extrinsic log-likelihoodratio (LLR) of bit u_(i) generated by the polar decoder for the n^(th)transmissions. It depends on the difference between LLR of bit u_(i) andthe input extrinsic-LLR of bit u_(i) to the polar decoder for n^(th)transmissions. During initialization, the node sets extrinsic-LLR(u_(i),2^(nd) tx)=0, for all i=3,4,5, and sets iteration number t to t=1.

For iteration t, the node performs the following steps:

-   -   1. Set a priori info of {u₀, u₁, u₂} to zero, set a priori info        u_(i) to extrinsic-LLR(u_(i), 2^(nd) tx) for i=3,4,5.    -   2. Run polar decoder of 1st transmission (e.g., polar decoder        505 a in the example of FIG. 5).        -   a. Input:            -   i. Extrinsic-LLR of repeated info bits {u_(i): i=3,4,5}                from polar decoder of 2nd transmission (e.g., polar                decoder 505 b in the example of FIG. 5).            -   ii. LLR of channel bits {y₁₀, y₁₁, . . . , y₁₇}                (received from demodulator)        -   b. Output: extrinsic-LLR(u_(i), 1st tx) for i=0,1,2,3,4,5.    -   3. Set the a priori info of information bits u_(i)        extrinsic-LLR(u_(i), 1^(st) tx) for i=3,4,5.    -   4. Run Polar decoder of 2nd transmission 505 b.        -   a. Input:            -   i. Extrinsic-LLR of repeated info bits {u_(i): i=3,4,5}                from Polar decoder of 1st transmission 505 a.            -   ii. LLR of channel bits {y₂₀, y₂₁, . . . , y₂₇}.        -   b. Output: extrinsic-LLR(u_(i), 2nd tx) for i=3,4,5.    -   5. If t<t_(max), increment t, and go back to Step 1.        Otherwise, run Step 1, generate overall LLR of info bits {u_(i):        i=0,1,2,3,4,5} using polar decoder of 1st transmission 505 a.        The node makes a hard decision of info bits {u_(i):        i=0,1,2,3,4,5} based on the overall LLR.

FIG. 6 illustrates an example of iterative decoding using an arbitrary Ndifferent transmissions in HARQ incremental redundancy, in accordancewith certain embodiments. In the example embodiment of FIG. 6, the Ntransmissions are the first transmission and (N−1) retransmissionsassociated with a same block of information bits in the HARQ process.Each transmission is associated with a polar decoder 605. In the exampleof FIG. 6, a first transmission is associated with polar decoder 605 a,a second transmission is associated with polar decoder 605 b, a thirdtransmission is associated with polar decoder 605 c, and an Nthtransmission is associated with polar decoder 605 n.

Let I_(i) denote the set of indices of all non-frozen bits with respectto the 1st transmission that are transmitted in the i^(th) transmissionfor any i≥1. Also let u_(I) _(i)

{u_(k): k ∈ I_(i)} denote the collection of bits whose indices withrespect to the 1st transmission is in

Let I_(i,j) denote a set of indices of non-frozen bits with respect tothe 1st transmission that are re-transmitted in both the i^(th) thej^(th) transmissions for any i<j. Also let u_(I) _(i,j)

{u_(k): k ∈ I_(i,j)} denote the collection of bits whose indices withrespect to the 1st transmission is in I_(i,j). For notationalsimplicity, let I_(i,+)

∪_(k=i+1) ^(N) I_(j,k) be the set of indices of non-frozen bitstransmitted in both the i^(th) transmission and all subsequenttransmissions. Similarly, let I_(−, j)

∪_(k=1) ^(j−1) I_(j,k) denote the set of indices of non-frozen bitstransmitted in both the i^(th) transmission and all previoustransmissions.

During initialization, the node sets extrinsic-LLR(u_(i), n^(th) tx)=0,for all i ∈ I_(n,+) and for all n=1,2, . . . N, and sets iterationnumber t to t=1.

For iteration t, the node performs the following steps, which aredescribed separately below for forward propagation and backwardpropagation.

For forward propagation, for each decoder for the n^(th) transmission,from n=1 to n=N, perform the following steps:

-   -   1. Extract and combine extrinsic-LLR from previous transmissions        extrinsic-LLR(u_(i), m^(th) tx) for i ∈ I_(m,n) and m=1,2, . . .        , n−1 to obtain extrinsic-LLR(u_(i), 1^(st) to (n−1)^(th) tx)        for i ∈ I_(−,n).    -   2. Set a priori info u_(−,n) to extrinsic-LLR(u_(i), 1^(st) to        (n−1)^(th) tx) for i ∈ I_(−,n) and set a priori info for all        other bits in u_(I) _(n) to zero.    -   3. Run polar decoder of n^(th) transmission.        -   i. Input:            -   1. Extrinsic-LLR of repeated info bits u_(−,n) from                polar decoders of previous transmissions.            -   2. LLR of channel bits y_(n)=(y_(n,0), y_(n,1), . . . ,                y_(n,2) _(M) ) (received from demodulator), where M=3                for the example shown in FIG. 1-3.        -   ii. Output: extrinsic-LLR(u_(i), n^(th) tx) for i ∈ I_(n).

For backward propagation, for each decoder for the n^(th) transmission,from n=N back to n=1, perform the following steps:

-   -   1. Extract and combine extrinsic-LLR from subsequent        transmissions extrinsic-LLR(u_(i), m^(th) tx) for i ∈ I_(m,n)        and m=n+1, n+2, . . . , N+1 to obtain extrinsic-LLR(u_(i),        (n+1)^(th) to N^(th) tx) for i ∈ I_(n,+).    -   2. Set the a priori info of information bits u_(m+) to        extrinsic-LLR(u_(i), (n+1)^(th) to N^(th) tx) for i ∈I_(n,+),        and set a priori info for all other bits in u_(I) _(n) to        extrinsic-LLR(u_(i), 1^(st) to (n−1)^(th) tx) for i ∈ I_(−,n).    -   3. Run Polar decoder of n^(th) transmission.        -   a. Input:            -   iii. Extrinsic-LLR of repeated info bits u_(n,+) from                polar decoders of all subsequent transmissions.            -   iv. LLR of channel bits y_(n).        -   b. Output: extrinsic-LLR(u_(i), n^(th) tx) for i ∈ I_(n).

If t<t_(max), increment t, and go back to Step 1. Otherwise, generateoverall LLR of all info bits u_(I) ₁ using polar decoder of 1sttransmission. Make hard decision of info bits u_(I) ₁ based on theoverall LLR.

While the decoding procedure is described above to illustrate the basicprinciple of utilizing soft information between multiple polar decoders,it is understood that many variations can be done. For example, incertain embodiments the a priori LLR may be modified, rather than beingused as is, in the polar decoder. One non-limiting example way to modifythe a priori LLR is to scale it by a factor. The value of the factor istypically a real number between 0.0 and 1.0. The factor may or may notbe the same for all constituent polar decoders.

In certain embodiments, after each of the n-th transmission (i.e.,(n−1)-th retransmission), 2≤n<N, the extrinsic LLR is stored. When N-thtransmission is received, the polar decoder corresponding to n-thtransmission, 2≤n<N are not re-run, but the extrinsic LLR of the n-thtransmission is retrieved from memory and used in the polar coder ofN-th transmission and first transmission. This has the benefit of neverhaving to run more than 2 polar decoders, even if there are more than 2HARQ (re-)transmissions done for one block of information bits.

FIG. 7 illustrates an example of how soft and hard information isgenerated in successive decoding of polar codes, in accordance withcertain embodiments. More particularly, FIG. 7 illustrates how soft andhard information can be generated for the length-8 Polar code describedabove in relation to FIGS. 1-3. Let y_(n)=(y_(n,0), y_(n,1), . . . ,y_(n,7)) be the LLR of channel bits received from a demodulator, andû_(i) denotes the hard decision made on the bit u_(i) for all t=0,1, . .. , 7.

Depending on the different bit positions of information bit u_(i),function g and f are applied for each node. The two functions areexpressed as g(a, b)=a(−1)^(û) ^(sum) +b and f(a, b)=2 tan h⁻¹(tanh(a/2)tan h(b/2)), respectively. The function h is used to decide theestimated bits from the LLRs when the trellis is traced to theinformation bit u_(i).

For information bits that use f(a,b) function before making harddecision, the hard decision is made using the modified expression:

LLR_(t,i)=LLR_(a,i) +f(a, b)

û _(i) =h(LLR_(t,i))

where LLR_(a,i) denotes the a priori information received on bit u_(i).And the extrinsic information for u_(i) is LLR_(e,i)=LLR_(t,i)−LLR_(a,i)=f(a, b).

For information bits that use g(a,b) function before making harddecision, the hard decision is made using the modified expression:

LLR_(t,i)=LLR_(a,i) +g(a, b)

û _(i) =h(LLR_(t,i))

And the extrinsic information for u_(i) isLLR_(e,i)=LLR_(t,i)−LLR_(a,i)=g(a, b).

Here LLR_(a,i) is the a priori LLR info of u_(i), which is a soft inputto the constituent polar decoder. And LLR_(e,i) is the extrinsic LLR ofu_(i), which is a soft output of the constituent polar decoder. Softvalue LLR_(t,i) is the total LLR of bit u_(i).

Function h(x) is the function that makes the hard decision û_(i) whichis an estimate of bit u_(i):

${h(x)} = \{ \begin{matrix}{{= 0},} & {{{if}\mspace{14mu} x} > 0} \\{{= 1},} & {{{if}\mspace{14mu} x} < 0}\end{matrix} $

Note that while many simplifications of the f(.) and g(.) functionsexist, here we use the basic expression for ease of discussion.

Although the above described example uses the typical description of aSC decoder to illustrate the iterative decoding principle, other typesof polar decoders can be used as well. Examples include, but are notlimited to, list decoding of SC decoder, BP (belief propagation)decoder, etc. The various types of polar decoders can be used togetherwith the iterative decoding principle, with soft information passingbetween two or more constituent polar decoders.

In particular, for list decoding, a different set of soft information(extrinsic LLRs) may be generated by each constituent polar decoder foreach candidate in the list of decoding paths. All these different setsof soft information may then be exchanged with other constituent polardecoders, so that list decoding can continue to be performed in thedecoding of other transmissions. As an alternative, to reducecomplexity, the LLR outputs for each candidate in the list can be addedto generate a single set of soft information (extrinsic LLRs) for thenext polar decoder. In addition, when calculating the output LLRs, thedecoder could also take into account the probability of observing thereceived signal assuming that the different candidates in the list werethe true codewords. In the case of CRC-aided list decoding, for exampleas described in Tal, each constituent polar decoder may produce andexchange soft information only for the candidate in the list of decodingpaths that passes CRC.

As a result of the foregoing embodiments, a decoder of a class ofrate-compatible polar codes is enabled to effectively take advantage ofthe aggregated block lengths after multiple transmissions to improve theblock error rate and the number of retransmissions needed to pass CRCfor a target block error rate.

While the processes in FIGS. 5-7 and the accompanying description mayshow a particular order of operations performed by certain embodiments,it should be understood that such order is exemplary (e.g., alternativeembodiments may perform the operations in a different order, combinecertain operations, overlap certain operations, etc.).

While the present disclosure has described several example embodiments,those skilled in the art will recognize that the present disclosure isnot limited to the example embodiments described, can be practiced withmodification and alteration within the spirit and scope of the appendedclaims. The description is thus to be regarded as illustrative insteadof limiting.

FIG. 8 is a flow diagram of a method 800 in a node, in accordance withcertain embodiments. Method 800 begins at step 804, where the nodereceives a plurality of transmissions associated with a given set ofinformation bits, wherein each of the plurality of transmissions use adifferent polar code and share one or more information bits of the givenset of information bits. In certain embodiments, the plurality oftransmissions associated with a given set of information bits maycomprise an initial transmission and a plurality of retransmissions.

At step 808, the node determines, at each of a plurality of polardecoders of the node, soft information for each information bit includedin an associated one of the plurality of transmissions, wherein each ofthe plurality of polar decoders is associated with a differenttransmission of the plurality of transmissions. The plurality of polardecoders may comprise successive cancellation decoders. In certainembodiments, the soft information may comprise one or more ofprobabilities or LLRs. In certain embodiments, the method may comprisescaling the soft information by a factor. In certain embodiments, thesoft information may be determined based on a LLR ratio of one or morechannel bits received from a demodulator and the soft informationprovided from the one or more other polar decoders of the plurality forany information bits shared by their respective associatedtransmissions. In certain embodiments, the method may comprise storingthe determined soft information.

At step 812, the node provides, from each polar decoder of the pluralityto one or more other polar decoders of the plurality, the determinedsoft information for any information bits shared by their respectiveassociated transmissions.

At step 816, the node uses the provided soft information in an iterativedecoding process to decode one or more of the received plurality oftransmissions. The soft information provided from the one or more otherpolar decoders of the plurality may comprise soft information from oneor more polar decoders of previous transmissions for a subset ofinformation bits shared by their respective transmissions. The softinformation provided from the one or more other polar decoders of theplurality may comprise soft information from one or more polar decodersof subsequent transmissions for a subset of information bits shared bytheir respective transmissions. In certain embodiments, the method maycomprise retrieving the stored soft information and using it to decode afirst transmission of the plurality of transmissions and anothertransmission of the plurality of transmissions.

In certain embodiments, the method may comprise determining, at a firstpolar decoder associated with a first transmission of the plurality oftransmissions, soft information for each information bit in the firsttransmission. The method may comprise providing, from the first polardecoder associated with the first transmission to a second polar decoderassociated with a second transmission, the soft information for eachinformation bit in the first transmission included in a subset ofinformation bits shared by the first transmission and the secondtransmission. The method may comprise determining, at the second polardecoder associated with the second transmission of the plurality oftransmissions, soft information for each information bit in the subsetof information bits shared by the first transmission and the secondtransmission. The method may comprise providing, from the second polardecoder associated with the second transmission to the first polardecoder associated with the first transmission, the soft information foreach information bit in the subset of information bits shared by thefirst transmission and the second transmission. In certain embodiments,the method may comprise determining, by the first polar decoder, a harddecision for each information bit of the first transmission based on thesoft information provided by the second polar decoder for eachinformation bit in the subset of information bits shared by the firsttransmission and the second transmission. FIG. 9 is a block schematic ofan exemplary UE 912, in accordance with certain embodiments. UE 912 isan example of a wireless device, such as wireless device 110 describedabove in relation to FIG. 4 (e.g., a wirelessly connected device, suchas in a vehicle), according to one exemplary embodiment that can be usedin one or more of the non-limiting example embodiments described above.UE 912 comprises a processing module 930 that controls the operation ofUE 912. Processing module 930 is connected to a receiver or transceivermodule 932 with associated antenna(s) 934 that are used to receivesignals from or both transmit signals to and receive signals from, forexample, a base station in a network (e.g., a network node 115 innetwork 100 described above in relation to FIG. 4). In certainembodiments, to make use of discontinuous reception (DRX), processingmodule 930 can be configured to deactivate receiver or transceivermodule 932 for specified lengths of time. UE 912 also comprises a memorymodule 936 that is connected to processing module 930 and stores programand other information and data required for the operation of UE 912. Insome embodiments, UE 912 may optionally comprise a satellite positioningsystem (e.g., Global Positioning System (GPS)) that receiver module 938that can use to determine the position and speed of movement of UE 912.

FIG. 10 is a block schematic of an exemplary eNB 1010, in accordancewith certain embodiments. eNB 1010 is an example of a network node, suchas network node 115 described above in relation to FIG. 4, that can beused in one or more of the non-limiting example embodiments describedabove. It will be appreciated that although a macro eNB will not inpractice be identical in size and structure to a micro eNB, for thepurposes of illustration, the base stations 1010 are assumed to includesimilar components. Thus, base station 1010 comprises processing module1040 that controls the operation of base station 1010. Processing module1040 is connected to transceiver module 1042 with associated antenna(s)1044 that are used to transmit signals to, and receive signals from,wireless devices (e.g., wireless devices 110 in network 100 describedabove in relation to FIG. 4, such as mobile devices (e.g., invehicles)). Base station 1010 also comprises memory module 1046 that isconnected to processing module 1040 and that stores program and otherinformation and data required for the operation of base station 1010.Base station 1010 also includes components and/or circuitry 1048 forallowing base station 1010 to exchange information with other basestations 1010 (for example via an X2 interface) and components and/orcircuitry 1049 for allowing base station 1010 to exchange informationwith nodes in the core network (for example via the Si interface). Itwill be appreciated that base stations for use in other types of network(e.g., UTRAN or WCDMA RAN) will include similar components to thoseshown in FIG. 10 and appropriate interface circuitry 1048, 1049 forenabling communications with the other network nodes in those types ofnetworks (e.g., other base stations, mobility management nodes and/ornodes in the core network). Another wireless device, such as a UE, couldact as a node, according to certain embodiments.

FIG. 11 is a block schematic of an exemplary wireless device 110, inaccordance with certain embodiments. Wireless device 110 may refer toany type of wireless device communicating with a node and/or withanother wireless device in a cellular or mobile communication system.Examples of wireless device 110 include a mobile phone, a smart phone, aPDA, a portable computer (e.g., laptop, tablet), a sensor, an actuator,a modem, a MTC device/M2M device, LEE, LME, USB dongles, a D2D capabledevice, or another device that can provide wireless communication. Awireless device 110 may also be referred to as UE, a station (STA), adevice, or a terminal in some embodiments. Wireless device 110 includestransceiver 1110, processing circuitry 1120, and memory 1130. In someembodiments, transceiver 1110 facilitates transmitting wireless signalsto and receiving wireless signals from network node 115 (e.g., viaantenna 1140), processing circuitry 1120 executes instructions toprovide some or all of the functionality described above as beingprovided by wireless device 110, and memory 1130 stores the instructionsexecuted by processing circuitry 1120.

Processing circuitry 1120 may include any suitable combination ofhardware and software implemented in one or more modules to executeinstructions and manipulate data to perform some or all of the describedfunctions of wireless device 110, such as the functions of wirelessdevice 110 described above in relation to FIGS. 1-8. In someembodiments, processing circuitry 1120 may include, for example, one ormore computers, one or more central processing units (CPUs), one or moremicroprocessors, one or more applications, one or more applicationspecific integrated circuits (ASICs), one or more field programmablegate arrays (FPGAs) and/or other logic.

Memory 1130 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by processing circuitry 1120. Examples ofmemory 1130 include computer memory (for example, Random Access Memory(RAM) or ROM), mass storage media (for example, a hard disk), removablestorage media (for example, a Compact Disk (CD) or a Digital Video Disk(DVD)), and/or or any other volatile or non-volatile, non-transitorycomputer-readable and/or computer-executable memory devices that storeinformation, data, and/or instructions that may be used by processingcircuitry 1120.

Other embodiments of wireless device 110 may include additionalcomponents beyond those shown in FIG. 11 that may be responsible forproviding certain aspects of the wireless device's functionality,including any of the functionality described above and/or any additionalfunctionality (including any functionality necessary to support thesolution described above). As just one example, wireless device 110 mayinclude input devices and circuits, output devices, and one or moresynchronization units or circuits, which may be part of the processingcircuitry 1120. Input devices include mechanisms for entry of data intowireless device 110. For example, input devices may include inputmechanisms, such as a microphone, input elements, a display, etc. Outputdevices may include mechanisms for outputting data in audio, videoand/or hard copy format. For example, output devices may include aspeaker, a display, etc.

FIG. 12 is a block schematic of an exemplary network node 115, inaccordance with certain embodiments. Network node 115 may be any type ofradio network node or any network node that communicates with a UEand/or with another network node. Examples of network node 115 includean eNB, a gNB, a node B, a BS, a wireless AP (e.g., a Wi-Fi AP), a lowpower node, a BTS, relay, donor node controlling relay, transmissionpoints, transmission nodes, RRU, RRH, MSR radio node such as MSR BS,nodes in DAS, O&M, OSS, SON, positioning node (e.g., E-SMLC), MDT, orany other suitable network node. Network nodes 115 may be deployedthroughout network 100 as a homogenous deployment, heterogeneousdeployment, or mixed deployment. A homogeneous deployment may generallydescribe a deployment made up of the same (or similar) type of networknodes 115 and/or similar coverage and cell sizes and inter-sitedistances. A heterogeneous deployment may generally describe deploymentsusing a variety of types of network nodes 115 having different cellsizes, transmit powers, capacities, and inter-site distances. Forexample, a heterogeneous deployment may include a plurality of low-powernodes placed throughout a macro-cell layout. Mixed deployments mayinclude a mix of homogenous portions and heterogeneous portions.

Network node 115 may include one or more of transceiver 1210, processingcircuitry 1220, memory 1230, and network interface 1240. In someembodiments, transceiver 1210 facilitates transmitting wireless signalsto and receiving wireless signals from wireless device 110 (e.g., viaantenna 1250), processing circuitry 1220 executes instructions toprovide some or all of the functionality described above as beingprovided by a network node 115, memory 1230 stores the instructionsexecuted by processing circuitry 1220, and network interface 1240communicates signals to backend network components, such as a gateway,switch, router, Internet, PSTN, core network nodes or radio networkcontrollers 130, etc.

Processing circuitry 1220 may include any suitable combination ofhardware and software implemented in one or more modules to executeinstructions and manipulate data to perform some or all of the describedfunctions of network node 115, such as those described above in relationto FIGS. 1-8. In some embodiments, processing circuitry 1220 mayinclude, for example, one or more computers, one or more CPUs, one ormore microprocessors, one or more applications, one or more ASICs, oneor more FPGAs, and/or other logic.

Memory 1230 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by processing circuitry 1220. Examples ofmemory 1230 include computer memory (for example, RAM or ROM), massstorage media (for example, a hard disk), removable storage media (forexample, a CD or a DVD), and/or or any other volatile or non-volatile,non-transitory computer-readable and/or computer-executable memorydevices that store information.

In some embodiments, network interface 1240 is communicatively coupledto processing circuitry 1220 and may refer to any suitable deviceoperable to receive input for network node 115, send output from networknode 115, perform suitable processing of the input or output or both,communicate to other devices, or any combination of the preceding.Network interface 1240 may include appropriate hardware (e.g., port,modem, network interface card, etc.) and software, including protocolconversion and data processing capabilities, to communicate through anetwork.

Other embodiments of network node 115 may include additional componentsbeyond those shown in FIG. 12 that may be responsible for providingcertain aspects of the radio network node's functionality, including anyof the functionality described above and/or any additional functionality(including any functionality necessary to support the solutionsdescribed above). The various different types of network nodes mayinclude components having the same physical hardware but configured(e.g., via programming) to support different radio access technologies,or may represent partly or entirely different physical components.

FIG. 13 is a block schematic of an exemplary radio network controller orcore network node 130, in accordance with certain embodiments. Examplesof network nodes can include a MSC, a serving GPRS support node (SGSN),a MME, a RNC, a BSC, and so on. The radio network controller or corenetwork node 130 includes processing circuitry 1320, memory 1330, andnetwork interface 1340. In some embodiments, processing circuitry 1320executes instructions to provide some or all of the functionalitydescribed above as being provided by the network node, memory 1330stores the instructions executed by processing circuitry 1320, andnetwork interface 1340 communicates signals to any suitable node, suchas a gateway, switch, router, Internet, PSTN, network nodes 115, radionetwork controllers or core network nodes 130, etc.

Processing circuitry 1320 may include any suitable combination ofhardware and software implemented in one or more modules to executeinstructions and manipulate data to perform some or all of the describedfunctions of the radio network controller or core network node 130. Insome embodiments, processing circuitry 1320 may include, for example,one or more computers, one or more CPUs, one or more microprocessors,one or more applications, one or more ASICs, one or more FPGAs, and/orother logic.

Memory 1330 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by processing circuitry 1320. Examples ofmemory 1330 include computer memory (for example, RAM or ROM), massstorage media (for example, a hard disk), removable storage media (forexample, a CD or a DVD), and/or or any other volatile or non-volatile,non-transitory computer-readable and/or computer-executable memorydevices that store information.

In some embodiments, network interface 1340 is communicatively coupledto processing circuitry 1320 and may refer to any suitable deviceoperable to receive input for the network node, send output from thenetwork node, perform suitable processing of the input or output orboth, communicate to other devices, or any combination of the preceding.Network interface 1340 may include appropriate hardware (e.g., port,modem, network interface card, etc.) and software, including protocolconversion and data processing capabilities, to communicate through anetwork.

Other embodiments of the network node may include additional componentsbeyond those shown in FIG. 13 that may be responsible for providingcertain aspects of the network node's functionality, including any ofthe functionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove).

FIG. 14 is a schematic block diagram of an exemplary wireless device, inaccordance with certain embodiments. Wireless device 110 may include oneor more modules. For example, wireless device 110 may include adetermining module 1410, a communication module 1420, a receiving module1430, an input module 1440, a display module 1450, and any othersuitable modules. In some embodiments, one or more of determining module1410, communication module 1420, receiving module 1430, input module1440, display module 1450, or any other suitable module may beimplemented using one or more processors, such as processing circuitry1120 described above in relation to FIG. 11. In certain embodiments, thefunctions of two or more of the various modules may be combined into asingle module. Wireless device 110 may perform the methods for softdecoding of rate-compatible polar codes described above in relation toFIGS. 1-8.

Determining module 1410 may perform the processing functions of wirelessdevice 110. In certain embodiments, wireless device 110 may perform thefunctions of the node described above. In such a scenario, determiningmodule 1410 may determine, at each of a plurality of polar decoders ofthe node, soft information for each information bit included in anassociated one of a plurality of transmissions, wherein each of theplurality of polar decoders is associated with a different transmissionof the plurality of transmissions. In certain embodiments, determiningmodule 1410 may determine the soft information based on a LLR of one ormore channel bits received from a demodulator and the soft informationprovided from the one or more other polar decoders of the plurality forany information bits shared by their respective associatedtransmissions. In certain embodiments, determining module 1410 may scalethe soft information by a factor.

As another example, determining module 1410 may use the provided softinformation in an iterative decoding process to decode one or more ofthe received plurality of transmissions.

As still another example, determining module 1410 may provide, from eachpolar decoder of the plurality to one or more other polar decoders ofthe plurality, the determined soft information for any information bitsshared by their respective associated transmissions. In certainembodiments, determining module 1410 may determine, at a first polardecoder associated with a first transmission of the plurality oftransmissions, soft information for each information bit in the firsttransmission. Determining module 1410 may provide, from the first polardecoder associated with the first transmission to a second polar decoderassociated with a second transmission, the soft information for eachinformation bit in the first transmission included in a subset ofinformation bits shared by the first transmission and the secondtransmission. Determining module 1410 may determine, at the second polardecoder associated with the second transmission of the plurality oftransmissions, soft information for each information bit in the subsetof information bits shared by the first transmission and the secondtransmission. Determining module 1410 may provide, from the second polardecoder associated with the second transmission to the first polardecoder associated with the first transmission, the soft information foreach information bit in the subset of information bits shared by thefirst transmission and the second transmission. Determining module 1410may determine a hard decision for each information bit of the firsttransmission based on the soft information provided by the second polardecoder for each information bit in the subset of information bitsshared by the first transmission and the second transmission.

As another example, determining module 1410 may store the determinedsoft information, for example in memory, such as memory 1130 describedabove in relation to FIG. 11. In certain embodiments, determining module1410 may retrieve the stored soft information and using it to decode afirst transmission of the plurality of transmissions and anothertransmission of the plurality of transmissions.

Determining module 1410 may include or be included in one or moreprocessors, such as processing circuitry 1120 described above inrelation to FIG. 11. Determining module 1410 may include analog and/ordigital circuitry configured to perform any of the functions ofdetermining module 1410 and/or processing circuitry 1120 describedabove. The functions of determining module 1410 described above may, incertain embodiments, be performed in one or more distinct modules.

Communication module 1420 may perform the transmission functions ofwireless device 110. In certain embodiments, wireless device 110 mayperform the functions of the node described above. In such a scenario,communication module 1420 may send (e.g., to a network node) a pluralityof transmissions associated with a given set of information bits,wherein each of the plurality of transmissions use a different polarcode and share one or more information bits of the given set ofinformation bits. Communication module 1420 may include a transmitterand/or a transceiver, such as transceiver 1110 described above inrelation to FIG. 11. Communication module 1420 may include circuitryconfigured to wirelessly transmit messages and/or signals. In particularembodiments, communication module 1420 may receive messages and/orsignals for transmission from determining module 1410. In certainembodiments, the functions of communication module 1420 described abovemay be performed in one or more distinct modules. Receiving module 1430may perform the receiving functions of wireless device 110.

In certain embodiments, wireless device 110 may perform the functions ofthe node described above. In such a scenario, receiving module 1430 mayreceive a plurality of transmissions associated with a given set ofinformation bits, wherein each of the plurality of transmissions use adifferent polar code and share one or more information bits of the givenset of information bits. Receiving module 1430 may include a receiverand/or a transceiver. Receiving module 1430 may include a receiverand/or a transceiver, such as transceiver 1110 described above inrelation to FIG. 11. Receiving module 1430 may include circuitryconfigured to wirelessly receive messages and/or signals. In particularembodiments, receiving module 1430 may communicate received messagesand/or signals to determining module 1410. The functions of receivingmodule 1430 described above may, in certain embodiments, be performed inone or more distinct modules.

Input module 1440 may receive user input intended for wireless device110. For example, the input module may receive key presses, buttonpresses, touches, swipes, audio signals, video signals, and/or any otherappropriate signals. The input module may include one or more keys,buttons, levers, switches, touchscreens, microphones, and/or cameras.The input module may communicate received signals to determining module1410. The functions of input module 1440 described above may, in certainembodiments, be performed in one or more distinct modules.

Display module 1450 may present signals on a display of wireless device110. Display module 1450 may include the display and/or any appropriatecircuitry and hardware configured to present signals on the display.Display module 1450 may receive signals to present on the display fromdetermining module 1410. The functions of display module 1450 describedabove may, in certain embodiments, be performed in one or more distinctmodules.

Determining module 1410, communication module 1420, receiving module1430, input module 1440, and display module 1450 may include anysuitable configuration of hardware and/or software. Wireless device 110may include additional modules beyond those shown in FIG. 14 that may beresponsible for providing any suitable functionality, including any ofthe functionality described above and/or any additional functionality(including any functionality necessary to support the various solutionsdescribed herein).

FIG. 15 is a schematic block diagram of an exemplary network node 115,in accordance with certain embodiments. Network node 115 may include oneor more modules. For example, network node 115 may include determiningmodule 1510, communication module 1520, receiving module 1530, and anyother suitable modules. In some embodiments, one or more of determiningmodule 1510, communication module 1520, receiving module 1530, or anyother suitable module may be implemented using one or more processors,such as processing circuitry 1220 described above in relation to FIG.12. In certain embodiments, the functions of two or more of the variousmodules may be combined into a single module. Network node 115 mayperform the methods for soft decoding of rate-compatible polar codesdescribed above with respect to FIGS. 1-8.

Determining module 1510 may perform the processing functions of networknode 115. In certain embodiments, network node 115 may perform thefunctions of the node described above. In such a scenario, determiningmodule 1510 may determine, at each of a plurality of polar decoders ofthe node, soft information for each information bit included in anassociated one of a plurality of transmissions, wherein each of theplurality of polar decoders is associated with a different transmissionof the plurality of transmissions. In certain embodiments, determiningmodule 1510 may determine the soft information based on a LLR of one ormore channel bits received from a demodulator and the soft informationprovided from the one or more other polar decoders of the plurality forany information bits shared by their respective associatedtransmissions. In certain embodiments, determining module 1510 may scalethe soft information by a factor.

As another example, determining module 1510 may use the provided softinformation in an iterative decoding process to decode one or more ofthe received plurality of transmissions.

As still another example, determining module 1510 may provide, from eachpolar decoder of the plurality to one or more other polar decoders ofthe plurality, the determined soft information for any information bitsshared by their respective associated transmissions. In certainembodiments, determining module 1510 may determine, at a first polardecoder associated with a first transmission of the plurality oftransmissions, soft information for each information bit in the firsttransmission. Determining module 1510 may provide, from the first polardecoder associated with the first transmission to a second polar decoderassociated with a second transmission, the soft information for eachinformation bit in the first transmission included in a subset ofinformation bits shared by the first transmission and the secondtransmission. Determining module 1510 may determine, at the second polardecoder associated with the second transmission of the plurality oftransmissions, soft information for each information bit in the subsetof information bits shared by the first transmission and the secondtransmission. Determining module 1510 may provide, from the second polardecoder associated with the second transmission to the first polardecoder associated with the first transmission, the soft information foreach information bit in the subset of information bits shared by thefirst transmission and the second transmission. Determining module 1510may determine a hard decision for each information bit of the firsttransmission based on the soft information provided by the second polardecoder for each information bit in the subset of information bitsshared by the first transmission and the second transmission.

As another example, determining module 1510 may store the determinedsoft information, for example in memory, such as memory 1230 describedabove in relation to FIG. 12. In certain embodiments, determining module1510 may retrieve the stored soft information and using it to decode afirst transmission of the plurality of transmissions and anothertransmission of the plurality of transmissions.

Determining module 1510 may include or be included in one or moreprocessors, such as processing circuitry 1220 described above inrelation to FIG. 12. Determining module 1510 may include analog and/ordigital circuitry configured to perform any of the functions ofdetermining module 1510 and/or processing circuitry 1220 describedabove. The functions of determining module 1510 may, in certainembodiments, be performed in one or more distinct modules.

Communication module 1520 may perform the transmission functions ofnetwork node 115. In certain embodiments, network node 115 may performthe functions of the node described above. In such a scenario,communication module 1520 may send (e.g., to a wireless device) aplurality of transmissions associated with a given set of informationbits, wherein each of the plurality of transmissions use a differentpolar code and share one or more information bits of the given set ofinformation bits. Communication module 1520 may transmit messages to oneor more of wireless devices 110. Communication module 1520 may include atransmitter and/or a transceiver, such as transceiver 1210 describedabove in relation to FIG. 12. Communication module 1520 may includecircuitry configured to wirelessly transmit messages and/or signals. Inparticular embodiments, communication module 1520 may receive messagesand/or signals for transmission from determining module 1510 or anyother module. The functions of communication module 1520 may, in certainembodiments, be performed in one or more distinct modules.

Receiving module 1530 may perform the receiving functions of networknode 115. In certain embodiments, network node 115 may perform thefunctions of the node described above. In such a scenario, receivingmodule 1530 may receive a plurality of transmissions associated with agiven set of information bits, wherein each of the plurality oftransmissions use a different polar code and share one or moreinformation bits of the given set of information bits. Receiving module1430 may include a receiver and/or a transceiver. Receiving module 1530may receive any suitable information from a wireless device. Receivingmodule 1530 may include a receiver and/or a transceiver, such astransceiver 1210 described above in relation to FIG. 12. Receivingmodule 1530 may include circuitry configured to wirelessly receivemessages and/or signals. In particular embodiments, receiving module1530 may communicate received messages and/or signals to determiningmodule 1510 or any other suitable module. The functions of receivingmodule 1530 may, in certain embodiments, be performed in one or moredistinct modules.

Determining module 1510, communication module 1520, and receiving module1530 may include any suitable configuration of hardware and/or software.Network node 115 may include additional modules beyond those shown inFIG. 15 that may be responsible for providing any suitablefunctionality, including any of the functionality described above and/orany additional functionality (including any functionality necessary tosupport the various solutions described herein).

Modifications, additions, or omissions may be made to the systems andapparatuses described herein without departing from the scope of thedisclosure. The components of the systems and apparatuses may beintegrated or separated. Moreover, the operations of the systems andapparatuses may be performed by more, fewer, or other components.Additionally, operations of the systems and apparatuses may be performedusing any suitable logic comprising software, hardware, and/or otherlogic. As used in this document, “each” refers to each member of a setor each member of a subset of a set.

Modifications, additions, or omissions may be made to the methodsdescribed herein without departing from the scope of the disclosure. Themethods may include more, fewer, or other steps. Additionally, steps maybe performed in any suitable order.

Although this disclosure has been described in terms of certainembodiments, alterations and permutations of the embodiments will beapparent to those skilled in the art. Accordingly, the above descriptionof the embodiments does not constrain this disclosure. Other changes,substitutions, and alterations are possible without departing from thespirit and scope of this disclosure, as defined by the following claims.

Abbreviations used in the preceding description include:

3 GPP 3^(rd) Generation Partnership Project

AP Access Point

ASIC Application Specific Integrated Circuit

BER Block Error Rate

BP Belief Propagation

BS Base Station

BSC Base Station Controller

BTS Base Transceiver Station

CD Compact Disk

CPE Customer Premises Equipment

CPU Central Processing Unit

CRC Cyclic Redundancy Check

D2D Device-to-device

DAS Distributed Antenna System

DL Downlink

DRX Discontinuous Reception

DVD Digital Video Disk

eNB evolved Node B

E-SMLC Evolved Serving Mobile Location Center

FPGA Field Programmable Gate Array

GPS Global Positioning System

GSM Global System for Mobile Communications

HARQ Hybrid Automatic Repeat Request

IoT Internet of Things

IP Internet Protocol

IR Incremental Redundancy

LAN Local Area Network

LDPC Low-Density Parity-Check

LEE Laptop Embedded Equipment

LLR Log-Likelihood Ratio

LME Laptop Mounted Equipment

LTE Long Term Evolution

M2M Machine-to-Machine

MAC Message Authentication Code

MAN Metropolitan Area Network

MAP Maximum A Posteriori

MCF, Multi-cell/multicast Coordination Entity

MCG Master Cell Group

MCS Modulation level and coding scheme

MDT Minimization of Drive Test

MeNB Master eNodeB

ML Maximum Likelihood

MME Mobility Management Entity

MSC Mobile Switching Center

MSR Multi-standard Radio

MTC Machine-Type Communication

NAS Non-Access Stratum

NB-IoT Narrow band Internet of Things

NR New Radio

O&M Operations and Management

OSS Operations Support System

PSTN Public Switched Telephone Network

RAM Random Access Memory

RAN Radio Access Network

RAT Radio Access Technology

RNC Radio Network Controller

ROM Read-Only Memory

RRC Radio Resource Control

RRH Remote Radio Head

RRU Remote Radio Unit

SC Successive Cancellation

SCG Secondary Cell Group

SCL Successive Cancellation List

SeNB Secondary eNodeB

SON Self-Organizing Network

UE User Equipment

UL Uplink

UMTS Universal Mobile Telecommunications System

VOIP Voice Over Internet Protocol

WAN Wide Area Network

WiMax Worldwide Interoperability for Microwave Access (WiMax)

WLAN Wireless Local Area Network

1. A method in a node, comprising: receiving a plurality oftransmissions associated with a given set of information bits, whereineach of the plurality of transmissions use a different polar code andshare one or more information bits of the given set of information bits;determining, at each of a plurality of polar decoders of the node, softinformation for each information bit included in an associated one ofthe plurality of transmissions, wherein each of the plurality of polardecoders is associated with a different transmission of the plurality oftransmissions; providing, from each polar decoder of the plurality toone or more other polar decoders of the plurality, the determined softinformation for any information bits shared by their respectiveassociated transmissions; and using the provided soft information in aniterative decoding process to decode one or more of the receivedplurality of transmissions.
 2. The method of claim 1, wherein the softinformation comprises one or more of probabilities or log-likelihoodratios.
 3. The method of claim 1, wherein the soft information isdetermined based on a log-likelihood ratio of one or more channel bitsreceived from a demodulator and the soft information provided from theone or more other polar decoders of the plurality for any informationbits shared by their respective associated transmissions.
 4. The methodof claim 3, wherein the soft information provided from the one or moreother polar decoders of the plurality comprises soft information fromone or more polar decoders of previous transmissions for a subset ofinformation bits shared by their respective transmissions.
 5. The methodof claim 3, wherein the soft information provided from the one or moreother polar decoders of the plurality comprises soft information fromone or more polar decoders of subsequent transmissions for a subset ofinformation bits shared by their respective transmissions.
 6. The methodof claim 1, comprising scaling the soft information by a factor.
 7. Themethod of claim 1, comprising: determining, at a first polar decoderassociated with a first transmission of the plurality of transmissions,soft information for each information bit in the first transmission;providing, from the first polar decoder associated with the firsttransmission to a second polar decoder associated with a secondtransmission, the soft information for each information bit in the firsttransmission included in a subset of information bits shared by thefirst transmission and the second transmission; determining, at thesecond polar decoder associated with the second transmission of theplurality of transmissions, soft information for each information bit inthe subset of information bits shared by the first transmission and thesecond transmission; providing, from the second polar decoder associatedwith the second transmission to the first polar decoder associated withthe first transmission, the soft information for each information bit inthe subset of information bits shared by the first transmission and thesecond transmission.
 8. The method of claim 7, comprising: determining,by the first polar decoder, a hard decision for each information bit ofthe first transmission based on the soft information provided by thesecond polar decoder for each information bit in the subset ofinformation bits shared by the first transmission and the secondtransmission.
 9. The method of claim 1, comprising storing thedetermined soft information.
 10. The method of claim 9, comprisingretrieving the stored soft information and using it to decode a firsttransmission of the plurality of transmissions and another transmissionof the plurality of transmissions.
 11. The method of claim 1, whereinthe plurality of transmissions associated with a given set ofinformation bits comprise an initial transmission and a plurality ofretransmissions.
 12. The method of claim 1, wherein the plurality ofpolar decoders comprise successive cancellation decoders.
 13. A node,comprising: processing circuitry, the processing circuitry configuredto: receive a plurality of transmissions associated with a given set ofinformation bits, wherein each of the plurality of transmissions use adifferent polar code and share one or more information bits of the givenset of information bits; determine, at each of a plurality of polardecoders of the node, soft information for each information bit includedin an associated one of the plurality of transmissions, wherein each ofthe plurality of polar decoders is associated with a differenttransmission of the plurality of transmissions; provide, from each polardecoder of the plurality to one or more other polar decoders of theplurality, the determined soft information for any information bitsshared by their respective associated transmissions; and use theprovided soft information in an iterative decoding process to decode oneor more of the received plurality of transmissions.
 14. The node ofclaim 13, wherein the soft information comprises one or more ofprobabilities or log-likelihood ratios.
 15. The node of claim 13,wherein the processing circuitry is configured to determine the softinformation based on a log-likelihood ratio of one or more channel bitsreceived from a demodulator and the soft information provided from theone or more other polar decoders of the plurality for any informationbits shared by their respective associated transmissions.
 16. The nodeof claim 15, wherein the soft information provided from the one or moreother polar decoders of the plurality comprises soft information fromone or more polar decoders of previous transmissions for a subset ofinformation bits shared by their respective transmissions.
 17. The nodeof claim 15, wherein the soft information provided from the one or moreother polar decoders of the plurality comprises soft information fromone or more polar decoders of subsequent transmissions for a subset ofinformation bits shared by their respective transmissions.
 18. The nodeof claim 13, comprising scaling the soft information by a factor. 19.The node of claim 13, wherein the processing circuitry is configured to:determine, at a first polar decoder associated with a first transmissionof the plurality of transmissions, soft information for each informationbit in the first transmission; providing, from the first polar decoderassociated with the first transmission to a second polar decoderassociated with a second transmission, the soft information for eachinformation bit in the first transmission included in a subset ofinformation bits shared by the first transmission and the secondtransmission; determine, at the second polar decoder associated with thesecond transmission of the plurality of transmissions, soft informationfor each information bit in the subset of information bits shared by thefirst transmission and the second transmission; provide, from the secondpolar decoder associated with the second transmission to the first polardecoder associated with the first transmission, the soft information foreach information bit in the subset of information bits shared by thefirst transmission and the second transmission.
 20. The node of claim19, wherein the processing circuitry is configured to: determine, by thefirst polar decoder, a hard decision for each information bit of thefirst transmission based on the soft information provided by the secondpolar decoder for each information bit in the subset of information bitsshared by the first transmission and the second transmission.
 21. Thenode of claim 13, wherein the processing circuitry is configured tostore the determined soft information.
 22. The node of claim 21, whereinthe processing circuitry is configured to retrieve the stored softinformation and use it to decode a first transmission of the pluralityof transmissions and another transmission of the plurality oftransmissions.
 23. The node of claim 13, wherein the plurality oftransmissions associated with a given set of information bits comprisean initial transmission and a plurality of retransmissions.
 24. The nodeof claim 13, wherein the plurality of polar decoders comprise successivecancellation decoders.